A user environment, such as a residence or an office building, for example, may be configured using various types of load control systems. FIG. 1 depicts a prior art user environment 100. The user environment 100 includes a wall-mounted load control device 110 coupled in series electrical connection between an AC power source 102 and a light bulb 112 installed in a ceiling mounted downlight fixture 114. The user environment 100 includes a table lamp 124 plugged into an electrical receptacle 126 that is powered by the AC power source 102. The table lamp 124 is plugged into an electrical receptacle 126 via electrical plug 120. Light bulb 122 is installed in table lamp 124. The wall-mounted load control device 110 has an electronic switch (e.g., light switch 116). In response to actuation of the light switch 116, the wall-mounted load control device 110 is configured to turn the light bulb 112 on and off.
The user environment 100 includes a battery-powered handheld remote control device 150 having buttons 152. The battery-powered remote control device 150 transmits RF signals 106 in response to actuations of one or more of the buttons 152. The light bulb 112 and light bulb 122 receive digital messages via radio-frequency (RF) signals 106. The RF signals 106 are transmitted by the battery-powered remote control device 150. In response to the received RF signals, the light bulb 112 and/or light bulb 122 turn on and off.
The user environment may include a bridge and a smartphone or tablet for controlling the light bulbs 112, 122. The bridge transmits RF signals to the light bulbs 112, 122. The bridge receives Wi-Fi signals from the smartphone or tablet for controlling the light bulbs 112, 122 and formats the information in the Wi-Fi signals for being received by the light bulbs 112, 122 on a different protocol.
In user environment 100, a problem arises if power is removed from the light bulb 112 and/or the light bulb 122. The problem arises whether or not a bridge is present in the user environment 100. For example, if power is removed from the light bulbs and returns to the light bulbs, the light bulbs turn on to a default intensity level (e.g., 100% intensity level). As an example, the light bulb 112 may be set to electronic off and the light bulb 122 may be set to an intensity level of eighty percent. Power may intentionally be removed from the light bulb 112 via an actuation of the light switch 116 to the off position. As another example, power may unintentionally be removed from the light bulb 112 and/or the light bulb 122 due a blackout or a brownout. Upon power being returned to the light bulb 112 and the light bulb 122, the light bulb 112 and light bulb 122 may present light at the default intensity (e.g., an intensity level of 100%). During unintentional power removal, it may be undesirable to a user for the light bulb 112 and light bulb 122 to present light at the default intensity. Rather, during an unintentional power removal, the user may desire that the intensity of the light bulbs be returned to their respective pre-power removal states (e.g., electronic off and eighty percent, respectively). For example, during an unintentional power removal, a user may not desire the light bulb 112 and/or the light bulb 122 to operate at the default state of full intensity when the user is asleep or when the user is away from the user environment 100 for an extended period of time. Accordingly, there is a need for the control system to distinguish between an intentional power removal event (based on a user action) and an unintentional power removal event (such as a blackout), so that the light bulbs may behave in an expected manner.